diff --git a/lightning/visualization.py b/lightning/visualization.py
index e3a0997..a18697c 100644
--- a/lightning/visualization.py
+++ b/lightning/visualization.py
@@ -41,7 +41,7 @@ def _append_image(self, image):
 
     def _append_data(self, data=None, field=None):
         payload = {'data': data}
-        headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}        
+        headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}
         url = self.session.host + '/sessions/' + str(self.session.id) + '/visualizations/' + str(self.id) + '/data/'
         if field:
             url += field
@@ -51,7 +51,7 @@ def _append_data(self, data=None, field=None):
 
     def _update_data(self, data=None, field=None):
         payload = {'data': data}
-        headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}        
+        headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}
         url = self.session.host + '/sessions/' + str(self.session.id) + '/visualizations/' + str(self.id) + '/data/'
         if field:
             url += field
@@ -194,7 +194,7 @@ def save_html(self, filename=None, overwrite=False):
                 os.remove(filename)
         with open(filename, "wb") as f:
             f.write(base.encode('utf-8'))
-            f.write('<script>' + js.encode('utf-8') + '</script>')
+            f.write(b'<script>' + js.encode('utf-8') + b'</script>')
 
     @staticmethod
     def load_template():
@@ -208,5 +208,3 @@ def load_embed():
         location = os.path.join(os.path.dirname(__file__), 'lib/embed.js')
         import codecs
         return codecs.open(location, "r", "utf-8").read()
-
-